An exit by Alaska's Ted Stevens may cost the GOP a key seat.

WASHINGTON — The indictment of Sen. Ted Stevens (R-Alaska) on corruption charges Tuesday throws into question his grip on a Senate seat he has held for decades and offers Democrats a chance to strengthen their hold on Congress.

Stevens, the longest-serving Republican in the Senate and a towering figure in Alaska's political history, was indicted by a federal grand jury here on charges that he concealed hundreds of thousands of dollars in gifts from one of the state's most powerful employers. The indictment accuses Stevens, 84, of accepting more than $250,000 in improvements to his Alaska home, as well as other gifts such as a gas grill and a new Land Rover, from VECO Corp., an oil field services company.

"It saddens me to learn that these charges have been brought against me," Stevens said in a statement in which he denied that he had ever knowingly submitted a false disclosure form. "I am innocent of these charges and intend to prove that."

Stevens said he had relinquished his post as senior Republican on several congressional committees in accordance with Senate GOP rules that require members indicted on felony charges to give up leadership posts.

Stevens has served in the Senate since 1968 and has held some of its most powerful positions, including chairmanships of the Appropriations and Commerce committees. He is legendary for bringing home federal dollars to Alaska; the Anchorage Daily News once wrote that Stevens was "the second-largest engine of the Alaska economy."

According to Citizens Against Government Waste, a Washington watchdog group, Stevens sponsored a total of 1,452 pork barrel projects worth $3.4 billion between 1995 and 2008, making Alaska the No. 1 state in pork per capita every year since 1999.

The indictment casts a shadow over Stevens' future. He is up for reelection this year, and news reports questioning his ethics have already damaged his standing. Alaska has not elected a Democratic senator for a generation. But even before Stevens was indicted, polls showed him trailing his Democratic opponent, Anchorage Mayor Mark Begich.

Stevens' defeat would be a big notch in the belt of Democrats hoping to expand their party's slim control of the Senate. (The chamber's two independents typically vote with the 49 Democrats against the 49 Republicans). Some analysts wonder whether Stevens will drop his bid for reelection rather than risk the loss of his seat to a Democrat. Several Republicans are running against Stevens in the state's GOP primary Aug. 26.

"If Stevens runs, the likelihood of him getting beaten in the primary just went up 100%," said Jennifer Duffy, who analyzes Senate elections for the nonpartisan Cook Political Report.

Reaction to the indictment Tuesday was muted on Capitol Hill, where the Justice Department has been conducting a number of corruption probes.

Sen. Richard J. Durbin (D-Ill.), the Senate's majority whip, described the mood among Democrats as "somber" and said his caucus was thinking of Stevens and his family. "I believe in the presumption of innocence," Durbin added. "At this point, we should just let the courts do their work."

Republicans largely avoided reporters.

Senate Minority Leader Mitch McConnell (R-Ky.) appeared alone before reporters at a regular briefing usually attended by most of the GOP leadership. He appeared grim and spoke briefly on Stevens. "The Republican conference, like you, just heard of this news," McConnell said. "No doubt we'll have more to say about this later." He turned from reporters' shouted questions and walked away.

Stevens is charged with seven counts of making false statements on his financial disclosure forms for calendar years 2001 to 2006. The post-Watergate Ethics in Government Act requires lawmakers to disclose gifts over a specific monetary amount as well as liabilities in excess of $10,000.

The indictment alleges that, over a six-year period, Stevens failed to report gifts from VECO, in exchange for which he "received and accepted solicitations for multiple official actions," including helping VECO obtain lucrative federal contracts and providing "assistance" with company ventures in Pakistan and Russia.

The indictment does not accuse him of the more serious crime of bribery. Legal experts said that may reflect difficulty that prosecutors had in identifying specific legislative favors that Stevens performed for VECO. Bribery law requires that there be an identifiable exchange, known as a quid pro quo, between a thing of value and an official act.

The charges culminate a multiyear influence-peddling investigation that has led to the convictions of several Alaska state officials and the chief executive of VECO, Bill J. Allen, who last year admitted that he made more than $400,000 in payments to government officials. Stevens' son, Ben, a former president of the Alaska state Senate, remains under federal investigation, as does Republican U.S. Rep. Don Young of Alaska.